H 145 aluminum head

duncan

The garage that was tuning up our 54 Hornet was driving it back to the shop that is finishing  the restoration and they got a 1/2 mile
from our shop when he heard a bang and car started to miss. Hi lifted the hood and found one of the spark plugs was laying on its side with some of the aluminum around the plug was broken. Has any body had this expperiance. It had new heilia coils installed in plug holes.  Ray

Uncle Josh

That won't happen if the Heli-coil was long enough and is installed with the right Heli-coil tool, and the hole hadn't been previously boogered.  However....

What you may have to do now, is have the hole enlarged and tapped to a larger thread and screw a piece of threaded aluminum in there and secure it with a 'Dutchman' ie a threaded screw (10-32?) on the outside of the thread that splits the thread so it can not rotate. Also secure the threads with Locktite or JB Weld.

The outside diameter of the Heli-coil is already .635 so you'll have to go to 3/4 (.750).  Then drill the plug and tap it 14mm for the spark plug.  The tap drill is 12.7mm (1/2 inch)

And where are you at with the other 5?

If it was me, I'd take the Aluminum head to the recycle place, and replace it with an iron head.  You'll have a lot less problems.

 

duncan

Thanks  Uncle Josh  That is what I am

Lance

Ray. If you need an iron 308 head let me know. I too have an aluminium Alcoa built 308 head.... hanging on the wall.

Browniepetersen

I have an aluminum head on the recent display motor that I purchased for the 308 Twin H for my 54.  That is about all they are good for in my opinion...

dave s

In my humble opinion, They make good lawn sprinklers!  I used 262 iron heads on all of my 308's, just ground numbers off top of head and no one notices the difference. :-)